feat(csms): add system settings management for OCPP 1.6J heartbeat interval

apps/csms/src/lib/system-settings.ts

@@ -0,0 +1,45 @@
+import { eq } from "drizzle-orm";
+import { systemSetting } from "@/db/schema.js";
+import { useDrizzle } from "@/lib/db.js";
+
+export const SETTINGS_KEY_OCPP16J = "ocpp16j";
+const DEFAULT_HEARTBEAT_INTERVAL = 60;
+const MIN_HEARTBEAT_INTERVAL = 10;
+const MAX_HEARTBEAT_INTERVAL = 86400;
+
+export type Ocpp16jSettings = {
+  heartbeatInterval: number;
+};
+
+export type SettingsPayload = {
+  ocpp16j: Ocpp16jSettings;
+};
+
+export function sanitizeHeartbeatInterval(raw: unknown): number {
+  if (typeof raw !== "number" || !Number.isFinite(raw)) {
+    return DEFAULT_HEARTBEAT_INTERVAL;
+  }
+  const n = Math.round(raw);
+  if (n < MIN_HEARTBEAT_INTERVAL) return MIN_HEARTBEAT_INTERVAL;
+  if (n > MAX_HEARTBEAT_INTERVAL) return MAX_HEARTBEAT_INTERVAL;
+  return n;
+}
+
+export function getDefaultHeartbeatInterval(): number {
+  return DEFAULT_HEARTBEAT_INTERVAL;
+}
+
+export async function getOcpp16jSettings(): Promise<Ocpp16jSettings> {
+  const db = useDrizzle();
+  const [ocpp16jRow] = await db
+    .select()
+    .from(systemSetting)
+    .where(eq(systemSetting.key, SETTINGS_KEY_OCPP16J))
+    .limit(1);
+
+  const ocpp16jRaw = (ocpp16jRow?.value ?? {}) as Record<string, unknown>;
+
+  return {
+    heartbeatInterval: sanitizeHeartbeatInterval(ocpp16jRaw.heartbeatInterval),
+  };
+}